When a driver of a vehicle is following directions output by her vehicle's navigation system while following a navigation route toward her destination, the navigation system may attempt to guide the driver onto or through a road that is closed. That is, the navigation route implemented by the navigation system passes through the closed road. In these instances, the driver would need to manually adjust the navigation route such that the navigation route avoids passing through the closed road. When driving in proximity to closed roads, the driver is typically within a construction zone. Construction zones usually have lower-than-expected speed limits that are identified by nonstandard signs. Construction zones are generally chaotic and in certain instances full of debris that may make its way onto the roadway. The driver must be ever-vigilant to recognize the speed limit changes and identify dangerous debris in the roadway. The driver may benefit from a system that monitors the vehicle's surroundings, predicts when the navigation route will pass through a closed road, preemptively modifies the navigation route to avoid the closed road, identifies changes in the speed limit, and identifies dangerous debris in the roadway.